In a large bowl, combine the ground beef, salt, black pepper, garlic powder, onion powder, diced onion, and diced bell pepper. Mix until well combined.
Form the mixture into 8 equal patties and place them in the bottom of the crockpot.
In a separate bowl, mix together the ketchup, mustard, and Worcestershire sauce. Pour this mixture over the patties in the crockpot.
Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the meat is cooked through and tender.
About 15 minutes before serving, place a slice of cheddar cheese on each patty, cover, and allow the cheese to melt.
Serve the cheeseburgers on hamburger buns with pickles, lettuce, and tomato if desired.